1. Field of the Invention
This invention relates generally to electronic equipment, such as computers, and, more particularly, to apparatus used during insertion and extraction of circuit boards from electronic systems.
2. Background Information
Electronic systems such as computers are typically constructed in a modular fashion. For example, a system may include number of circuit boards, each circuit board generally performing a specific function. Each circuit board requires multiple electrical connections, which are generally provided by two part multi-contact electrical connectors. One part of the connector is mounted to the circuit board, while a mating part of the connector may be attached to another component of the system such as a rack, a chassis, a cable, or another circuit board (e.g., backplane circuit board). Successful mating of connector parts is needed for reliable electrical connections in the system. The system may include other modules, such as power supplies, disk drives, and fan tray assemblies.
A number of mechanisms are known for injecting a module into a chassis or extracting a module from a chassis. Such mechanisms may include levers pivotally coupled to the circuit board and arranged to engage projections formed on the chassis. Guide formations may be provided on the chassis to receive the module and to guide the module into position. The levers may be arranged on the circuit board such that when the lever are actuated, the circuit board is provided with a biasing force that serves to move the circuit board toward the rear of the chassis. The biasing force is used to mate the parts of the electrical connector on the module with corresponding connector parts in the chassis.
For circuit boards with connectors having a relatively large number of pins, large insertion forces may be required to mate the connector parts. For example, a large board may contain several multi-contact connectors, each connector containing several hundred individual contacts. Each contact requires the application of an insertion force to seat the contact. Thus, the total insertion force required to seat a large board may be 65 pounds or more. Moreover, individual contacts are easily damaged if the mating connector parts are not properly aligned when they come into contact with each other. This problem is especially acute where large forces are required to mate the connector parts.
Injection/extraction mechanisms, and the mounting hardware associated with the mechanisms, consume space near the front of a module. The size of some mechanisms may require that the width and/or height of a slot for a given module be increased. Portions of a mechanism (e.g., lever arms) may also take up space outside a front panel of a module. In addition, apertures must be provided in the module, chassis, and/or EMI seals to provide clearance for the levers and/or other hardware. Electromagnetic radiation may pass through the apertures, creating electromagnetic interference with the system.